Reducer - Easy Extraction of Code Reduction Tool Runs from Projects

A tool to invoke reduction tools cvise or creduce on C++ files inside of a project. Handles extraction of the file from the project into a work directory, and auto-preprocesses the file if the error remains, and tries repeating pre-processing after convergence of the reduction tool for even smaller reproducers.

The tool is based on drivers invoked via top-level commands (tidy, compiler-crash).

Here is an example for a clang-tidy crash (the default for the tidy driver):

reducer.py tidy \
           --build-dir /path/to/problematic/build/ \
           --file /path/to/problematic/file.cpp

What this invocation does:

• extract file.cpp into a separate working directory
• extract the corresponding compile command from compile_commands.json
• get the clang-tidy config for this file and write a .clang-tidy config file in the working directory
• try to deduce the crashing check from the enabled checks for this file by scanning the crash message, and falling back to binary search
• pre-process the file if it retains the error
• set up the interestingness test by first compiling the code with the compiler specified in the compilation command, and then calling clang-tidy
• run the interestingness test

The tool can also reduce broken clang-tidy fixes (--require-post-compile), support grepping for false-positives, and timeouts.